Engine System Fault - Limp Mode

I was driving down the freeway with the cruise control engaged doing 65 miles an hour when all of the sudden my dash displays the message Engine System Fault and the car went into limp mode with a rpm restriction of 2000 rpm. I shifted into neutral and shut the car off while still in motion on the freeway and then restarted. The problem still existed, so I pulled off the freeway, stopped and shut the car off. One minute later I restarted the vehicle and the problem went away. I drove home without incident. Any ideas what happened and how to fix it. I used my code scanner and it shows no codes.